The invention discloses a human K-ras (K-rat sarcoma) gene mutation parting type fluorescent quantitation PCR (polymerase chain reaction) detecting reagent kit and a detecting method. The detecting reagent kit comprises PCR mixed reaction liquid, a peptide nucleic acid probe, a taqman-MGB (minor groove binder) probe, an inner control forward and reverse primer and probe, an external control forward and reverse primer and probe and a positive reference article, wherein the inner control forward and reverse primer and probe is used for K-ras gene mutation detection, and the external control forward and reverse primer and probe is used for the K-ras gene mutation detection. The PNA (peptide nucleic acid) technology and the taqman-MGB technology are combined, relevant ARMS (amplification refractory mutation system) primers are designed, PNA can be stably combined with wild K-ras genes 12 or 13 codon sequences, only mutation specimens can be amplified, and the K-ras gene mutation can be detected. The method has the advantages that the speed is high, simplicity and convenience are realized, the specificity is good, the sensitivity is high, and the method can be used for the clinical K-ras gene mutation screening.